This invention relates to a new and improved hand held electronic manometer and is more particularly concerned with such a manometer comprising a self-contained assembly which may have a pressure modulating device.
Although, as will become apparent, the present invention may serve advantageously for determining and modulating fluid pressure in many situations, an important utility resides in providing for convenient, substantially accurate monitoring in the course of various intra-body surgical procedures, information as to fluid pressure, either gas or liquid, for any of several reasons such as safety of involved body tissues, surgical performance, and the like. For example, where anesthetic is administered to a patient by using an endotracheal tube having an inflatable cuff which is inflated by a source of pressurized air, proper inflation of the cuff should be monitored to assure that the endotracheal tube is properly restrained against slippage but not over-inflated to the point of damage of the mucosal wall of the trachea. In another procedure involving heart chamber and related arterial pressure, the pressure should be critically monitored, and may also require modulation.
Hand held gas pressure regulating and monitoring devices, utilizing a mercury column for visually indicating pressure such as in endotracheal tube procedures, are disclosed in Pistillo U.S. Pat. No. 4,526,196 and Shah U.S. Pat. No. 4,583,917. While the devices disclosed in those patents provide exceptionally desirable small, convenient, hand held units, the mercury for translating pressure into a mercury column pressure gauge requires that the device be maintained in a reasonably vertical position for attaining the desired accuracy of pressure readout during use of the device. Further, although ample safety precautions are built into the patented devices, there is sometimes resistance to use of the devices in surgical procedures for fear of mercury contamination.